Piston cooling



July 31, 1928. 1,678,957

0. PHILIPP PISTON COOLING Filed Jam. 22. 1926 Patented July 31, 1928.

UNITED STATES'PATENT OFFICE.

OTTO PHILIPP, OF WINTERTHIIR,.SWITZERLAND, ASSIGNOR T BOSGH-SULZEB BROS.- DIESEL ENGINE COMPANY, OF ST. LOUIS, MISSOURI, A CORPORATION OF MISSOURI.

PISTON COOLING.

Application filed January 22, 1926, Serial No. 82,947, and in Germany January 29, 1925. v I

The invention relates to engine pistons of the kind in which heat is dissipated from the working face or head wall of the piston by means of a body of heat-carrying material which is thrown back and forth within the piston by the reciprocation of the latter, so

material along such walls, thereby tending to tact with thejouter surface of the head wall as to have alternate contact with said head wall and with the lower or outer part of the piston, thus on each stroke carrying to the latter part of the heat which it takes from the head wall. The object is to improve this system of piston coollng 1n respect of its compactness and efliciency and to this end the invention consists in the principle of configuration of the piston as hereinafter explained.

In the accompanying drawing Figure 1 is an axial section of so much of a piston and cylinder of an internal combustion engine as will be necessary to illustrate one form of the invention. Figure 2 is a similar sectlon illustrating a different shape of the interior piston chamber; and Figure 3 an axial section of a further modified form of piston chamber.

In the drawing the piston cylinders 1 are water-jacketed or equivalently externally cooled and are understood to be provided with fuel injectors as indicated, or with other means of introducing combustible whereby combustion is caused to occur in the combustion spaces, as will be understood. In Figure 1 the piston is formed with an interior chamber immediatel adjacent to its head wall 2. This chamber is herein termed a heat-transfer chamber and entrance to it is closed by the screw plug, as indicated, orv in any other suitable manner. The chamber contains a body of mobile materlal 3 of good heat coeflicient, which is thrown back and forth in the chamber as the piston reciprocates. Such material may consist of copper or aluminum chips or of mercury, being in any event a material which does not change its form by the effect of the heat to which it is subjected inside of a piston. The heat transfer chamber is of greater diameter than length, so that the heat-carrying material has a relatively short flight from one wall to the other and practically the whole of the surface against which such material impinges is inclined to the direction of piston movement so that after impingement there is a considerable sliding of the and as it passes outer dead center is in contact with the opposite wall marked 4;, the latter being substantially parallel to the head wall 2 which in this case is conical. In the first mentioned position the mobile material'takes on a portion of heat from the head wall, particularly its center which is the hottest spot, and in the other position it delivers such heat piston, where it ma through the piston s water jacket. the water 7 ing the chamber walls 2 and 4 of progressively greater thickness as they approach the cylinder wall. s

In Figure 2 the head wall 5 of the piston 1s reentrant or dished and the disposition of the heat transfer chamber is accordingly modified, being in fact merely inverted as compared to Figure 1. This chamber is permanently closed by a cap-plate 6, but, like the chamber of Figure 1, is of considerable diameter and' relatively short axial dimension and the major portion of its internal wall surface is inclined to the direction of piston movement for the pu se to the outer part of the fin'd an escape path irt to thesurrounding The transfer of the heatito above explained and so that the materialtends to flow along rather than strike the chamber wall.

The piston of Figure 3 is constructed of a head and a skirt part marked 7 and 8, respectively, fitted together in any appropriate manner; and forming between them a heattransfer chamber operating on the same prolong the contact of the material with the jacket is also facilitated by formt pointed funnel holes on the upstroke of the .piston than through the others and vice versa on the down-stroke of the piston. This accomplishes an efiective distribution of the material and a longer contact of it with the metallic surfaces between which heat is exchanged. The transverse Wall 11 is relatively massive in section, so that, notwithstanding the apertures through it, it provides an easy escape path for the heat, in addition to which, he lower chamber wall 13 carries ofl heat as in the other figures.

It will now be apparent that the principles above explained can be applied to various types and designs of engine pistons and it will be understood that there is no intention to limit the scope of the appended claims to the specific piston designs which have been taken for illustration'ot the invention.

The following is claimed: I

An engine piston formed with a heattransfer chamber adjacent its head Wall, said chamber being of greater diameter than axial length and containing a mobile heat-carrying medium adapted to be thrown back and forth therein, the interior wall of said chamber presenting an imperforate surface and the major porton thereof being inclined to the direction of piston movement to control the movement of the medium as described.

In testimony whereof, I have signed this specification.

OTTO PHILIPP. 

